Wheelchairs or wheeled walkers have been widely used for aged or disabled people as a convenient vehicle. In many wheelchairs or wheeled walkers a brake is provided for emergency situations. Conventionally, the operator grasps a brake lever to pivot with respect to handlebar for effecting a brake. The pivot movement of the brake lever induces a stretching movement of the transmission cable connected at one end to the brake lever. Finally, the stretching movement of the transmission cable modifies the position of a brake mechanism mounted on a wheel of the wheelchair or the wheeled walker so as to reduce the speed or stop the wheelchair or the wheeled walker.
In the conventional handle brake devices, the brake lever is pivotally attached to a housing about a single pivot and the transmission cable is attached through a connector to the brake lever. Accordingly, the connecting position between the transmission cable and the brake lever remains fixed relative to the single pivot. Therefore, in these conventional devices, the movement of the transmission cable is not differentiated according to various operational positions of the brake lever. Considering that the resistance of the transmission cable is often higher at the end of the braking, when the brake lever is close to the handlebar, than at the beginning of the braking, when the brake lever is distant from the handlebar, it is often difficult, especially for persons with small hands, to transmit a sufficient force on the brake lever permitting to stop completely the wheelchair. In this case, the force torque executed by the hand of the operator on the brake lever is independent of the angular position of the brake lever.
One solution to this problem consists to modify the position of the connecting point of the transmission cable with regard to the pivot of the brake lever during the braking. Indeed, by modifying the position of the connecting point, it is possible to adapt the distance between the connecting point and the pivot in relation to the position of the brake lever. Therefore, by keeping constant the traction force of the operator on the brake lever and by reducing the distance between the connecting point and the pivot, the stretching force exerted on the transmission cable should be higher. Such a solution can be found for instance in the U.S. Pat. No. 5,279,179. The brake device for bicycle, revealed by this prior art, uses a force transmission ratio adjusting means for moving the connecting point of the transmission cable toward, and away from, the brake lever pivot. However, this solution is relatively complex and imposes the use of a specific cable connector.
The aim of the present invention is therefore to provide a handle brake device permitting to adapt the distance between the connecting point and the pivot in relation to the position of the brake lever, said device being simple to manufacture and easy to be manipulated. A further aim of the present invention is to provide a handle brake device in which the force torque executed by the hand of the operator on the brake lever is depending on the angular position of the brake lever.